Method of producing a heating or welding flame



Dec. 20, 1932.

s. w. MILLER 1,891,314

METHOD 0F PRODUCING A HEATING OR WELDING FLAME Original Filed May l5, 1928 yfi? Z 0 Z7 Z7 ZZ Patented Dee. 20,1932

c UNITED STATES iPA'llazN'rl f oFFIcE SAMUEL w. MILLER, or HoLLIs, NEW Yoan, nss'IeNon To-oxwELD acETYLn'Nn COMPANY, n CORPORATION' or WEST VIRGINIA METHOD or rnoDUcING .a HEATING on WELDING FLAME Application illed lay 15, 1 928, Serialy No. 278,024.l Renewed July 28, 1930.

This invention relates tothe art of heating and fusion welding of metals, and more particularly to a method of producing a heating or welding flame wherein the heating value of the fuel gas is more completely .utllized by introducing auxiliary oxygen lmto the combustion zone.

It is Well known in the Welding art that an Oxy-acetylene welding or heating iame is hottest when the acetylene is burned with an equal volume of oxygen, and that a iiame containing a substantial excess of either gas has an injurious eiiect upon certain metals such as steel. It is also well known that the oxyfacetylene flame burns in two stages.- In the primary stage the acetylene ncombines with the oxygen that has been mixed with it in the welding torch to form a combustible mixture andproduces hydrogen 'and carbon monoxide. In the secondary stage the hydrogen and carbon monoxide combine with the oxygen of the air and produce water vapor and carbon dioxide. Much of the heat evolved during secondary combustion is wasted be- 'not burn until after they'have passed the portion of the metal being welded or heated. The principal object of this invention is to accelerate the secondary combustion andl cause it to occur sooner and closer to the work being welded so that more of the heat units in the fuel gas will be utilized -in the weldingY operation. Other important objects are to eiect an economy in the volume of gases required to produce an eiiicient welding flame; and to render it possible to, employ a higher welding speed with a given volume of the welding gases. These and other objects and the novel features of my invention will appear from the following description taken with the accompanying drawing which illustrates a blowpipe for attaining the objects of this invention. In the drawing,

Fig.' 1 is a longitudinal sectionalview of an Oxy-acetylene Welding blowpipe;

Fig. 2 is a transverse sectional lview of the blowpipe in Fig. 1, taken along the line 22,

showing the construction of the valve controlling the auxiliary oxygen supply to the weldingpflame; and,

x Fig. 3 is a view ofy the outer end of the welding tip of F igl, showing the relative positions of the heating' or welding ilame orifices and auxiliary oxygen orifice.

Broadly speaking, my improved method of producing aheating or weldin flame con-l sists in first mixing a suitable el, such as acetylene or other hydrocarbon,with suicient oxygen to support the primary combustion'of the fuel. In order to accelerate the secondary combustion and cause it to take place closer to the weld that is bein produced, a relatively small volume of addltional v oxygen, preferably commercially pure' oxygen, is injected into4 the lcombustion zone. This auxiliary oxygen combines with the products of the primary combustion and roduces a greater amount of local heat t an l when these products are burned in the presence of air farther away from the primary combustion zone. This action is intensified when the ame is presented to the piece to be welded. Too great an amountof auxiliary oxy en will oxidize portions of the elements in t e, metal .being welded, but the auxiliary oxygen supply as well as the oxygen mixed with the fuel gasare independently regulated and so controlled that the total volume lof oxygen employed will be insuiicient to render the ame detrimentally oxidizing when such fialne is used for heating or welding metal. A .limited oxidation of the silicon, man anese, `carbon and iron-in the metal is .usua ly not objectionable; onthe contrary, it produces additional heat for the welding op"- eration. I have found that the use of a relatively small volume of oxygen in a flame according to my invention has decided advantages in fusion welding particularly, since it results in a more completeutilization' ofgthe heat units of the fuel gas and due to the additional heat rendered available at 'the welding point, the welding may beedone more rapidly, thus economizing gas, time and laborin the welding operatlon.,

I am aware `that free oxygen has been projected through-a combustlon zone, as in the' well lmown Oxy-acetylene cutting blowpipe used for cutting metals, but the cutting oxygen valve in suchblowpipes is purposely so arranged that it opens wide very quickly'so as to deliver an oxygen jet of large volume at high pressure for cutting by oxidizing or burning away the metal along the line of the cut. My method relates to fusion welding as distinguished from cutting, and in it I employ a very much smaller volumefof free oxygen of very low pressure, andregulate the supply of oxygen so that the total quantity of oxygen shall be insuflicient to render the fiame detrimentally oxidizing when used for fusion welding of metal.

The welding blowpipe shown for the purpose of illustrating the invention is composed of a metallic head 10 and a metallic tail member '11 connected by three metal pipes or tubes 12, 13, and 14, which may be soldered into sockets providedin the head and tail members in the usual manner. A tip 15 of suitable metal is secured tothe head 10 by any convenient means suchas a detachable nut 16 A flexible tube conveying oxygen in the form of an oxygen concentrate (preferably commercially pure oxygen) from the usual cylinder of compressed oxygen to the blowpipe may be connected to ltheta'il 11 by means of a nipple 17; and a similar tube tonveying acetylene or other fuel gas from the usual cylinder of dissolved Aor compressed fuel gas to the torch `may b'e connected to the tail memberll by means of a nipple 18. A conduit 19 within the tail 11 conducts -oxygen from the inlet nipple 17 to the tube 12 and its volume may be controlled by a valve 20. A conduit 21 in the tail member 11 conducts oxygen from the inlet nipple 17 to the tube 13 and its volume may be controlled by a valve 22. A conduit 23 within the tail member 11 conducts acetylene from the acetylene inlet nipple 18 to the tube 14 and its volume may be controlled by a valve 24. Conduits 25 and 26 in the head 10 conduct oxygen and acetylene'respectively fromthc tubes '12 and 14 to a conduit 27 where they mix and pass into a mixing and distributing chamber 28.

From the chamber 28 the mixture of fuel gas and oxygen passes out through conduits 29 in the tip 15. Oxygen entering the tube 13 passes through a conduit 30 in the head 10.and from there out through a centraliconduit 31 in the tip 15. The valves 20, 22, and 24, are vconstructed so the ressure and vol ume of the gas passing through each of them may be accurately and independently controlled.

` Four combustible gas passages 29 terminating in a series of four orifices arranged in the circumference of a circle are shown in the tip 15. This particular number is not im-v portant as I have secured good results with either a circle of orifices or an annular orifice arranged to produce a hollow ame intol duced through an orifice at the delivery end of the central oxygen passage 31. The arrangement of the orifices may be reversed and the auxiliary oxygen introduced around a central fiame but I have secured greater economy of the gases and greater speed in welding with the arrangement shown. The central auxiliary oxygen orifice should preferably be somewhat larger than the cutting oxygen orifice of a cutting torch to reduce the velocity of the issuing gas, as the oxygen combines with the partially burned gases more rapidly and -gives better results when itcffis discharged at a much lower velocity as compared with the cutting oxygen jet.

In practicing the process herein described the operation ofthe Welding torch shown in the accompanying illustrationis as follows: The valve 24 is partiallybpened permittin acetylene to flow through the tube 14, hea conduits 26 and 27, distributing chamber 28, tip conduits 29, and discharge from the outlet orifices of the conduits 29. The escaping acetylene is ignited and the size of itsflame is regulated in the usual manner by adjust` ing the valve 24. Then the valve 20is partially opened permitting oxygen to `flow throughthe tube 12 and conduit 25 into the conduit 27 where it mixes with the acetylene forming a combustible mixture that passes out through the chamber 28 and conduits 29.

e passages or conduits inside the torch where, prior to its delivery from the orifices of the passages 29, oxygen is mixed with the acetylene to form a mixture that will support primary combustion, I choose to term the pre-combustion zone. The valves 20 and .into the welding fiame at the combustion zone I term auxiliary oxygen to distinguish it from the oxygen that is mixed with the acetylene in the pre-combustion zone.

The welding operation may now be started.

As the metal being welded commences to fuse further adjustment of the auxiliary oxygen controlvalve 22 may be necessary as more' auxiliary oxygen may be required when welding some metals than others. Iftoo small an amount of auxiliary oxygen is used the welding speed will be too low and the full advantages of this process will not be obtained.l If too large an amount of auxiliary oxygen is used some metals such as steel will be burned to a detrimental extent. This latter condition is indicated by an unusually large when an excess oxygen flame .is used in welding as heretofore practicedr It is believed that when metals are welded in ordinary atmosphere. they are burned somewhat but not to a detrimental extent, and I have found that the heat of the welding flame mayy concentrated uponvthe weld and the welding speed substantially'increased by the introduc- I' tion of auxiliary oxygen into the combustion zone without burning the metal to a detrimental extent, if indeed any more than with the neutral welding flame ordinarily used.-

In welding one-half inch steel plate I have Y, successfull used avoluine of auxiliar o A- the acetylene), if mixed directly with they gen in the combustion. zone that was 20% of the volume of oxygen supplied to the mixture in the precombustion. zone. Thus, by injecting part of the oxy en into the combustion zgne I have successu of oxygen that was 1.2 times the volume of the acetylene used and the welding speed of the flame was considerably4 increased without detrimentally burning the metal. xBut a like quantity of oxygen (11.2 times the volume of acetylene y...in the pre-combustion zone, is impractical for heating or welding purposes because itdecreases the `welding speed of the flame and detrimentally-burns themetal.

I have demonstrated that auxiliary oxygenY introduced into the combustion zone produces a different effect upon the welding flame from that produced when additional .oxygen is mixed with the usual Oxy-acetylene mixture in the pre-combustion zone, and I believe the difference in action-to be as follows: The oxyacetylene flame is hottest when the acetylene is mixed with an equal quantity of oxygen in the pre-combustion zone, because thisis the correct mixturel for complete primary combustion.' Also, most of the heat that does the welding .is derived from the primary coinbustion. A large part of the secondary combustion occurs after thecombustible gases have passed the area being welded because the secondary combustion is supported by the oxygen of the air, and'so takes place over a large area instead .of being concentrated as in the case of the primary combustion. Also, the secondary combustion is comparatively slow, and the'welding area is near the beginning of its zone. Therefore, when an excess of oxygen is mixed with the acetylene in the re-combustion zone there is more than enough in the mixture to complete primary combustion, and the. excess oxygen absorbs heat as it passes through-the zone of' primary combustion thereby lowering the r flame temperature. Some of this excess oxygen may combine with the products of the primarycombustion to helpsupport the secondary combustion, but much of it reaches the fused metal first and burns the latter;

lly used a volume what is left helps in the 'secondary ,combusf tion, but beyond "the welding area, so that .l

the lieat from the combustion supported by such excess oxygen is either wasted or has a detrimental' "effect, Now, when auxiliary oxygenjs properly injected into the combustion zone according to my improved procedure it does not lower' the temperature of the primary combustion" but, instead, combines with the products ofthe primary combustion at the welding area, producinga large'amount of heat where it can be used for melting the metal, instead of being wasted beyond the welding area.. Therefore, an excess of'oxygen introduced into the pre-combustionl zone re-A duces the welding speed, but auxiliary oxygen introduced into the combustion zone so stimulates and localizes secondary combus tion that a greater welding speed may be employed. 1

I have already indicated thatthe free oxygen jet which is passed through the combustionzone, as in the well known Oxy-acetylene cutting torch, operates in a way that differs radically from my invention. Because of the very high velocity of such a jet, sbstantially none of it can aist in supporting either the `primary or the secondary combustion in the heating flame. AIt is used solely for the purpose of oxidizing heated metal to produce a'cut. The following test data will vsure of the auxiliary oxygen was about oneeighth of a pound and its velocity at the orifice only about 7 5 feet per second. In general.` therefore, the auxiliary oxygen for heating and welding'must be so regulated that its velocity will be so low that substantially none of it passes beyond the combustion zone;'

whereas the cutting oxygen is invariably lsol regulated that its pressure is high enough to. carry all of it beyond the combustion zone.

While the description of the process described herein has been confined to .an -oxyacetvlene flame for the sake ofsimplicity. auxiliary oxygen may.` nevertheless, be used to advantage with the flames of other hydrocarbons or fuel gases. Also` oxygen in other forms such as the oxygen of the air may be mixed with the fuel in place of `an oxygen concentrate to support primary combustion. Furthermore, the auxiliary oxygenfmay be introduced into the combustion zone by methods different from those shown. These and y other changes may be made in the method lof practicing the process Without from'the invention. 4

departing I claim:

1. The method of producing a heating .orv

oxygen with the hydrocarbon in the pre-combustion zone to support primary combustion; injecting additional oxygen into the combustion zone to stimulate and localize the secondary combustion; and so regulating the total quantity of' oxygen employed that it shall be insuflicient to render the flame detrimentally 'oxidizing when used for heating or Welding metal.

2. The method'of producing a Welding or heating flame which comprises passing a stream of acetylene through a pre-combustion zone to a combustion zone; mixing oxygen With the acetylene in the pre-combustion zone to support primary combustion; injecting additional oxygen into the combustion zone to stimulate and localize the secondary combustion;- and so regulating 'the total quantity of oxygen employed that it shall be insufficient to render the flame detrimentally oxidizing when used for Welding or heating metal.

I3. The method of producing a Welding flame Which comprises passing a stream of hydrocarbon gas through a pre-combustion zone to a combustion zone; mixing oxygen as an oxygen concentrate with the hydrocarbon in the pre-combustion zone tosupport primary combustion; injecting ladditional oxy as an oxygen concentrate into the combustion zone to stimulate and localize the secondary combustion; and so regulating the total quantity of oxygen employed that it shall be insuflicient to render the flame detrimentally oxidizing when used for fusion Welding of metals.

4. The method of producing a heating or Welding flame which comprises passing a stream of hydrocarbon gas through a precombustion zone to a combustion zone; vmixing oxygen with the hydrocarbonjn the precombustion zone to support primary combustion; injecting additional oxygen into the combustion zone to stimulate and localize the secondary combustion; and independently so regulating the supply of oxygen to the precombustion zone and the supply f additional oxygen to the combustion zone that the total quantity of oxygen employed shall be insufficient to render the flame detrimentally Noxidizing when used for heating or Welding metal., p

5. The method of producing a welding flame which comprises passing a stream of acetylene through a pre-combustion zone to a combustion zone mixing oxygen as an oxygen concentrate with the acetylene in the precombustion z one to support primary combustion; and injecting additional oxygen as an oxygen concentrate into the combustion zone to stimulate and-localize' the secondary combustion; the total quantity o oxygen employed being insuflicie'nt to render the flame detrimentally oxidizing when used for fusion Welding. p

6. The method of producing a flame adapted for fusion Welding of metals which comprises passing a stream of acetylene through a pre-combustion zone to a combustion zone; mixing oxygen as an oxygen concentrate with the acetylene in the pre-combustion yzone to support primary combustion; injecting additional oxygen as an oxygen concentrate into only suflicient oxygen with the hydrocarbon in the pre-combustion zone to support substantially complete primary combustion; injectingadd-itional oxygen into the combustion zone to stimulate and localize secondary combustion; and so regulating the supply of such additional oxygen that the quantity thereof passing beyond thevcombustion zone shall be insuliicient to render said flame detrimentally oxidizing when used for heating or Welding'metal.

8. The method of producing a heating or welding flame which comprises passing a stream of hydrocarbon through a pre-coml bustion zone to a combustion zone; mixing oxygen with the hydrocarbon in thepre-comlio bustion zone to support primary combustion;

injecting additional oxygen into the inner portion only of the combustion zone tostimulate and localize the secondary combustion; and so regulating the total quantity of oxygen employed that it shall be insufficient to render the flame detrimentally oxidizing when used for heating or Welding metal.

9. The method of producing a Welding flame which comprises passing a stream of acetylene through a pre-combustion zone to a combustion zone; mixing oxygen as an oxyf gen concentrate with the acetylene in the precombustion zone to support primary combustion; injecting additional oxygen as an oxygen concentrate into the inner portion only of the combustion zone to stimulate and localv ize the secondary combustion; and independently regulating both the oxygen supplies so that the total quantity ot oxygen employed shall be insuicient to render the ame detrimentally oxidizing when used for fusion welding of metals. v

10. The method of producing a flame 5 adapted for fusion Weldlng of metals which comprises passing a stream of acetylene through a pre-combustion zone to a combustion zone; mixing oxygen as an oxygen concentrate with the acetylene in the pre-coml bustion zone; regulating such oxygen to supply only a suilicient quantity for complete primary combustion of the acetylene; injecting additional oxygen as an oxygen concentrate substantially centrally into the come l bustion zone to stimulate and localize the secondary combustion; and independently so regulating the supply of additional oxygen that the quantity of oxygen employed shall be insuicient to render the flame detrimen- W tally oxidizing when used for fusion welding of metals.

11. The method of producing a heating flame which comprises adding oxygen to a hydrocarbon; burning said mixturein air; B5 and adding oxygen to the iame in addition to that supplied by the air to concentrate the heat in an arealsmaller than that occupied when no oxygen is added to the flame. i

12. The method of producing a heating iiame which comprises adding oxygento a c hydrocarbon; burning said mixture in air; and adding oxygen to the flame in addition to that supplied bythe air in a quantity just suiiicient to stimulate secondary combustion and concentrate the ame.

llllhe method of producing a heating flame which comprises adding oxygen to a hydrocarbon in a quantity sufficient to supt port primary combustion; burning said mxture 1n air; and adding oxygen to theflame in addition to that supplied by the air in a quantity just suicient 'to complete secondary combustion and stimulate and localize the ame. In testimony whereof, I aix my signature.

y SAMUEL W. MILLER. 

